github.com/greenboxal/deis@v1.12.1/docs/using_deis/process-types.rst (about) 1 :title: Process Types and the Procfile 2 :description: First steps for using the 12 factor process model with Deis. 3 4 .. _process-types: 5 6 Process Types and the Procfile 7 ============================== 8 9 A Procfile is a mechanism for declaring what commands are run by your application’s containers on 10 the Deis platform. It follows the `process model`_. You can use a Procfile to declare various 11 process types, such as multiple types of workers, a singleton process like a clock, or a consumer 12 of the Twitter streaming API. 13 14 Process Types as Templates 15 -------------------------- 16 17 A Procfile is a text file named ``Procfile`` placed in the root of your application that lists the 18 process types in an application. Each process type is a declaration of a command that is executed 19 when a container of that process type is started. 20 21 All the language and frameworks using :ref:`Heroku's Buildpacks <using-buildpacks>` declare a 22 ``web`` process type, which starts the application server. Rails 3 has the following process type: 23 24 .. code-block:: console 25 26 web: bundle exec rails server -p $PORT 27 28 All applications using :ref:`Dockerfile deployments <using-dockerfiles>` have an implied ``cmd`` 29 process type, which spawns the default process of a Docker image: 30 31 .. code-block:: console 32 33 $ cat Dockerfile 34 FROM centos:latest 35 COPY . /app 36 WORKDIR /app 37 CMD python -m SimpleHTTPServer 5000 38 EXPOSE 5000 39 40 For applications using :ref:`Docker image deployments <using-docker-images>`, a ``cmd`` process 41 type is also implied and spawns the default process of the image. 42 43 Declaring Process Types 44 ----------------------- 45 46 Process types are declared via a file named ``Procfile``, placed in the root of your app. Its 47 format is one process type per line, with each line containing: 48 49 .. code-block:: console 50 51 <process type>: <command> 52 53 The syntax is defined as: 54 55 ``<process type>`` – an alphanumeric string, is a name for your command, such as web, worker, urgentworker, clock, etc. 56 57 ``<command>`` – a command line to launch the process, such as ``rake jobs:work``. 58 59 .. note:: 60 61 The web and cmd process types are special as they’re the only process types that will receive 62 HTTP traffic from Deis’s routers. Other process types can be named arbitrarily. 63 64 Deploying to Deis 65 ----------------- 66 67 A ``Procfile`` is not necessary to deploy most languages supported by Deis. The platform 68 automatically detects the language and supplies a default ``web`` process type to boot the server. 69 70 Creating an explicit Procfile is recommended for greater control and flexibility over your app. 71 72 For Deis to use your Procfile, add the Procfile to the root of your application, then push to Deis: 73 74 .. code-block:: console 75 76 $ git add . 77 $ git commit -m "Procfile" 78 $ git push deis master 79 ... 80 -----> Procfile declares process types: web, worker 81 Compiled slug size is 10.4MB 82 83 Launching... done, v2 84 85 -----> unisex-huntress deployed to Deis 86 http://unisex-huntress.example.com 87 88 For Docker image deployments, a Procfile in the current directory or specified by 89 ``deis pull --procfile`` will define the default process types for the application. 90 91 Use ``deis scale web=3`` to increase ``web`` processes to 3, for example. Scaling a 92 process type directly changes the number of :ref:`Containers <container>` 93 running that process. 94 95 Web vs Cmd Process Types 96 ------------------------ 97 98 When deploying to Deis using a Heroku Buildpack, Deis boots the ``web`` process type to boot the 99 application server. When you deploy an application that has a Dockerfile or uses :ref:`Docker 100 images <using-docker-images>`, Deis boots the ``cmd`` process type. Both act similarly in that they 101 are exposed to the router as web applications. However, The ``cmd`` process type is special because 102 it is equivalent to running the :ref:`container` without any additional arguments. Every other 103 process type is equivalent to running the relevant command that is provided in the Procfile. 104 105 When migrating from Heroku Buildpacks to a Docker-based deployment, Deis will not convert ``web`` 106 process types to ``cmd``. To do this, you'll have to manually scale down the old process type and 107 scale the new process type up. 108 109 110 .. _`process model`: https://devcenter.heroku.com/articles/process-model